How to Invoice as a HVAC Technician in Washington

How to invoice as a hvac technician in Washington: WA sales tax 6.50% (applies to services), late fees capped at 1.5%/mo under Wash. Rev. Code §19.52.020. Step-by-step guide with a free template.

State sales tax
6.5%
Late fee cap
1.5%/mo
Net terms
7 days
Deposit
25%
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1. Washington-specific invoice requirements

  • Sales tax line: 6.50% state rate. Services billed to WA customers must include sales tax. State 6.5%; many services taxable. Combined commonly 8.5-10.5%.
  • Late-fee cap: Washington statute Wash. Rev. Code §19.52.020 caps interest on unpaid invoices at 1.5% per month. Spell out the rate in writing on every invoice and in your contract — courts won't enforce undisclosed fees.
  • Right-to-cancel notice: Customers in Washington get 72-hour cancellation rights on certain home-services contracts. Disclose this in your terms.

2. HVAC Technician line items + standard terms

Every hvac technician invoice in Washington should itemize work clearly. Standard hvac technicians use Net 7 terms with a 25% deposit required upfront.

  • Diagnostic fee — billed by flat (~$89 default).
  • Labor — billed by hour (~$115 default).
  • Refrigerant / parts — billed by itemized.
  • Service agreement credit — billed by discount.

3. HVAC Technician licensing in Washington

EPA Section 608 certification required for refrigerant work. State HVAC licenses common.

4. Send and follow up

Send the invoice the same day work completes. Use software that records open events and offers a one-click online payment so you don't need to chase a check by mail. Washington customers expect digital payment options today — accepting card and ACH typically reduces days-to-paid by 30–50%.

Average invoice
$540
State
WA
Net terms
7 days
Deposit
25%

Washington metro guides

Metro-specific guides include the combined sales-tax rate and local pricing benchmarks.

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